Voltage is an important parameter in circuits. It is the potential difference between the two charged points per unit charge in an electric field. In this article, we will discuss about voltage, voltage symbols, voltage units, voltage properties, voltage formulas, and types of voltages. We will also cover how to measure voltage.

What is Voltage?

Voltage is the amount of pressure required to move an electric charge (electrons) from one point to another in an electrical circuit. Voltage is also known as “electrical potential difference”, “electric tension” or “electric pressure”, it is the difference in electric potential of two points in an electric circuit.

Voltage Symbol

Voltage is denoted by the symbol V. Below diagram represents the symbol of voltage.

Voltage Unit

Voltage is measured in the unit “Volt”. One volt is equal to one joule of energy per coulomb of charge. A “Voltmeter” measures the voltage between two points in a system.

Properties of Voltage

Some properties of Voltage are listed below:

• Its SI unit is volt(V).
• In Equations and circuit diagrams, it is represented by symbol “V”.
• It defines the electric potential difference between two points in an electrical circuit.
• It is a scalar quantity.
• It has magnitude but it does not have a specific direction.
• It describes the magnitude of potential difference between two points, but it does not indicate the direction of current flow in a circuit.
• Various sources, like batteries, generators, power supplies, and photovoltaic cells can generate it.

Formula of Voltage

The formula of voltage can be determined in two ways:

• Voltage formula using work done and electric charge
• Voltage formula using Ohm’s law
• Voltage formula using Power and current
• Voltage formula using Power and resistance

Voltage Formula Using Work Done and Electric Charge

In terms of static electric field, mathematically voltage is defined as the amount of work done(W) to move an electrical charge(Q).

Voltage(V) = Work done(W) / Charge(Q)

Voltage Formula Using Ohm’s Law

In terms of Ohm’s law, the voltage is defined by the product of resistance of the conductor and current flowing through it.

Voltage(V) = I * R

where,

• I stand for current flowing in amperes (A).
• R stands for resistance in ohms (Ω).

Voltage Formula Using Power and Current

In terms of power and current, voltage is defined by the ratio of power by current flowing through it.

V = P / I

where,

• V is voltage
• P is power
• I is current

Voltage Formula Using Power and Resistance

In terms of power and resistance, voltage is defined by the square root of product of power and resistance.

V = √(P × R)

where,

• V is voltage
• P is power

Types of Voltage

Voltage is classified into two types based on the direction and magnitude of current flowing:

• AC (Alternating Current) voltage
• DC (Direct Current) voltage

DC (Direct Current) Voltage

DC (Direct Current) voltage maintains a constant direction and the electricity flows in a certain direction. The direct current voltage may be a constant voltage or a pulsating voltage. If it is a constant voltage, then the magnitude of voltage does not change with respect to time, while if it is a pulsating voltage, the magnitude changes with respect to time. It is mainly used in battery devices, smartphones, laptops, and electric vehicles (EVs).

AC (Alternating Current) Voltage

AC voltage alternates the voltage direction periodically, it changes from positive to negative and from negative to positive, and the direction of the current also periodically changes accordingly. The magnitude of the voltage changes continuously and direction also changes periodically. It is mainly used in household appliances, lighting systems, and electronic devices.

How to Measure Voltage?

There are several ways to measure voltage that are mentioned below.

Measure Voltage Using Voltmeter

Voltage between two points in a system can be measured by using a Voltmeter. Voltmeter is used to measure the voltage of an Alternating Current (AC) circuits or Direct Current (DC) circuits. The voltmeter connected across the two points measures the voltage drop between them when the current flows through the circuit.

There are two types of Voltmeters are:

• Analog Voltmeter
• Digital Voltmeter

Analog Voltmeter

Analog voltmeters provide continuous readings and are suitable for measuring both AC and DC voltages. Analog voltmeter has a pointer or needle to indicate the voltage on a scale. They have a moving coil or moving iron design. Due to digital voltmeter, these days analog voltmeter is less common usage.

Digital Voltmeter

Digital voltmeter contains voltage readings as numerical values on a digital screen. They are more accurate and easier to read than compared to analog voltmeters. The digital multimeter measures and displays the voltage readings on an LCD screen in the form of digits. The main advantage of using digital voltmeter is we can measure both direct voltage and alternating voltage with the same device just by changing the meter settings such as ac voltage and dc voltage.

Applications of Voltage

Voltage plays an important role in some electrical circuits and electrical applications. Here are few examples how voltage is used in daily-life applications:

• Car batteries like electric cars have voltage around 350 volts.
• Normal AA alkaline battery have voltage of 1.5 Volts.
• High voltage transmission lines carry voltages of 100,000 volts or more volts.
• Cell phone battery like lithium battery contains voltage around 3.7 volts charge.
• USB ports on computers and chargers typically provide a voltage of 5 volts.

Conclusion

From the above discussion we can conclude that the voltage is main part of electrical circuit and is given by the product of current and resistance present in the circuit. Also, there are two types of voltage: Alternating Current voltage and Direct current voltage. Voltage is measured using the voltmeter.

Voltage – FAQs

What is the Purpose of Voltage?

The purpose of the voltage is to move charged electrons through a conductor.

How is Voltage Measured?

Voltage between two points in a system can be measured by using a Voltmeter.

What Creates Voltage?

Voltage is created by a difference in electric charge between two points. It can be generated by various means, which include batteries, generators, and power supplies, these create an electric potential difference.